Tonight, from 19:55 to 20:00 we turned off all our lights to express concern over global warming. It was neat. We watched the buildings across the street and as people turned off their lights, they came out onto their balconies. We waved at each other and felt connected. Here in Barcelona, the lights were turned off at the Sagrada Familia and other tourist buildings. In Paris, they turned off the lights at the Tour Eiffel.